Case trimming the 45-70 for COL of 2.550

B

Bill Daniel

New member
To get a COL of 2.550” with the Hornady 325 grain FTX I have to trim the case to about 1.97”. This leaves a case capacity of about 44 grains of IMR 4198. This load is below maximum but is right at 100% capacity to slightly compressed to crimp at the cannelure of this bullet. Will a this load generate excess pressure (above SAAMI recomendations) due to the shortened case even though the powder charge is below max.?
My rifle Henry H010 will not cycle the Hornady LeverRevolution cartridge due to its COL being longer than 2.550”. I do like the improved trgectory of the FTX. I get about 1800 fps with 43 grains of IMR 4198 and wanted to check 44 grains also but am concerned with possible excess pressure since I changed the case capacity.
Thanks in advance,
Bill
 
CAUTION: The following post includes loading data beyond or not covered by currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assumes any liability for any damage or injury resulting from use the of this information.

QuickLOAD thinks 44 grains will be getting pretty close to the same peak pressure a full-length case would give you with Hornady's maximum load for a Marlin 1895, but not over it. What I don't know is if your particular gun can handle the same pressures as the Marlin.
 
https://en.wikipedia.org/wiki/.45-70

To get a COL of 2.550” with the Hornady 325 grain FTX I have to trim the case to about 1.97”.
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I have never trimmed the head of the case so I will assume you are trimming the mouth of the case. I measure case length from the mouth of the case to the case head, when measuring case overall length I always assume the 'overall' includes the bullet. It has never occurred to me it was possible to shorten the 'overall length by trimming the case. For me it has always been to shorten the overall length by seating the bullet deeper.

I do not want to confuse other reloaders but I do shorten cases for short chambers when 'the short' means the chamber is short from the shoulder to the bolt face.

F. Guffey
 
I have never trimmed the head of the case so I will assume you are trimming the mouth of the case. I measure case length from the mouth of the case to the case head, when measuring case overall length I always assume the 'overall' includes the bullet. It has never occurred to me it was possible to shorten the 'overall length by trimming the case. For me it has always been to shorten the overall length by seating the bullet deeper.
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COL stands for cartridge overall length, not case overall length. If you're seating a bullet into a crimping groove or cannalure on the bullet it's going to shorten the COL if you trim the case shorter. There's no getting around that. This isn't that complicated if you reference common loading manuals and use the terminology that's already in existence and universally accepted.
 
This isn't that complicated if you reference common loading manuals and use the terminology that's already in existence and universally accepted
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I have a machine that applies a cannalure, the machine does not get a lot of use because I do not crimp cases for the sake of crimping and I do not use neck tension. I use bullet hold.

And then the OP went on to say something about high pressure. Before seating the bullet he shortened the case .125", so if I was crimping and the bullet had a groove that was not exactly where I wanted it I would choose not to crimp. But if I had no choice I would crimp in the groove.

If it was absolutely necessary to crimp in the groove I would place a new groove on the bullet.

F. Guffey
 
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